1. Field
The present disclosure relates generally to a vehicle, and more particularly to an electric hybrid vehicle.
2. Related Art
Electric vehicles (EVs) are vehicles that utilize one or more electric motors for propulsion. Plug-in hybrid electric vehicles (PHEVs) utilize one or more electric motors and one or more rechargeable energy storage system (RESS, e.g. a battery) that powers these motors in combination with a conventional (e.g., combustion powered) powertrain. The RESS of EVs and PHEVs may recharge from a number of sources including fossil fuels, nuclear power, or renewable sources such as solar power, wind power, and the like.
Some governments provide incentives for purchase of EVs. In Denmark, for example, EVs are exempt from an initial tax, which amounts to 180% of the purchase price for gasoline vehicles. Denmark and Norway, among other governments, currently employ tax incentives to reduce fossil fuel consumption for transportation. These incentives aim to encourage the adoption of clean technologies such as electric vehicles. Electric vehicles do not emit greenhouse gasses (CO2), Nitrous Oxides (NOx), particulates, or carbon monoxide (CO) and can refuel from proven renewable energy technologies such as wind, solar, geothermal, and hydro (dams and tidal energy).
To qualify as an electric vehicle under these incentives, vehicles must meet certain criteria. Moreover, regulators in Denmark and Norway are evaluating additional criteria to allow plug-in hybrid electric vehicles (PHEVs) to apply for the tax incentives.
For example, regulators may require that a range-extending engine of a vehicle not activate until a user (e.g., driver) makes a deliberate manual selection, and after the onset of a low-range indicator. Furthermore, the low-range indicator may only illuminate once the battery of the vehicle has a charge that provides less than a predetermined electric range e.g., 15 km). The low-range indicator will deactivate once the user plugs the vehicle in and charges the vehicle past the low-range limit (e.g., 15 km). In addition, the vehicle must complete at least three new European driving cycles (NEDCs) under electric power only (i.e., without assistance from the range-extending engine and without recharging) in standard conditions. The distance the vehicle can achieve in this manner defines its all-electric range (AER).
A PHEV, however, cannot take advantage of the aforementioned incentives, even if it has the capability to run fully electric. This is because while some PHEVs can function as pure electric vehicles, the engine may still operate at times for various reasons such as, high-power demand, anticipated high power demand, preservation of the battery or other components, evaporative emissions purge, maintenance, extreme temperatures, or the like.
In a high power demand scenario, the user can select a vehicle mode in which the engine will run to aid in vehicle performance. For example, some vehicles enable the user to switch the operating mode of the vehicle from a standard mode to a “sport” mode to enhance performance. In an anticipated high power demand scenario, a vehicle may use its navigation to anticipate power and energy demands, such as, an impending hill, or the like. The vehicle may then turn on the engine to charge the battery in advance in order to avoid decreased performance at low battery levels, or to avoid inefficient regimes of operation. In a preserve battery or other component scenario, the engine will turn on to power a PHEV before the battery energy depletes because rechargeable batteries degrade quickly when the vehicle discharges them deeply. Any vehicle with a fuel system produces evaporative emissions, even when the engine does not run. Gasoline evaporates, and daily temperature fluctuations cause pressure fluctuations in the fuel system. The fuel system vents vapors when relieving this pressure, but can capture them in a carbon canister. A vehicle may run the engine to burn these vapors. A vehicle may also run its engine for maintenance reasons. A vehicle may run the engine when the electric powertrain is outside its preferred operating temperatures. The engine may run to provide heat to the passengers and to warm up the electric drive system. While running the engine under the aforementioned scenarios can be useful, running the engine when it is not necessary may be objectionable to regulators and customers.